Molecular and Morphological Data Support the Existence of a Sexual Cycle in Species of the Genus Paracoccidioides

Abstract

The genus Paracoccidioides includes the thermodimorphic species Paracoccidioides brasiliensis and P. lutzii, both of which are etiologic agents of paracoccidioidomycosis, a systemic mycosis that affects humans in Latin America. Despite the common occurrence of a sexual stage among closely related fungi, this has not been observed with Paracoccidioides species, which have thus been considered asexual. Molecular evolutionary studies revealed recombination events within isolated populations of the genus Paracoccidioides, suggesting the possible existence of a sexual cycle. Comparative genomic analysis of all dimorphic fungi and Saccharomyces cerevisiae demonstrated the presence of conserved genes involved in sexual reproduction, including those encoding mating regulators such as MAT, pheromone receptors, pheromone-processing enzymes, and mating signaling regulators. The expression of sex-related genes in the yeast and mycelial phases of both Paracoccidioides species was also detected by realtime PCR, with nearly all of these genes being expressed preferentially in the filamentous form of the pathogens. In addition, the expression of sex-related genes was responsive to the putative presence of pheromone in the supernatants obtained from previous cocultures of strains of two different mating types. In vitro crossing of isolates of different mating types, discriminated by phylogenetic analysis of the ␣-box (MAT1-1) and the high-mobility-group (HMG) domain (MAT1-2), led to the identification of the formation of young ascocarps with constricted coiled hyphae related to the initial stage of mating. These genomic and morphological analyses strongly support the existence of a sexual cycle in species of the genus Paracoccidioides.

Fatal Fungemia due to Paracoccidioides lutzii

“…The molecular characterization of the mating type idiomorph was carried out by polymerase chain reaction (PCR) using the primers MAT1-1F and MAT1-1R targeting MAT1-1 (α-box), and MAT1-2F and MAT1-2R targeting MAT1-2 (HMG) as described by Teixeira and others. 11 Isolate 9840 is a heterothallic strain harboring the MAT1-1 locus ( Figure 4B and C).…”

Asexual Propagation of a Virulent Clone Complex in a Human and Feline Outbreak of Sporotrichosis

“…As a result, it is not uncommon that the core genes required for sexual development are found in the genomes of limiting-sex fungi (32,55). In asexual pathogenic fungi such as Paracoccidioides brasiliensis, Paracoccidioides lutzii, and A. fumigatus, the sex-related genes were identified in their genomes prior to identification of sexual morphology (56,57). In our investigation, different pathways of mating processes present in the genomic architecture of sexual fungi, such as the mating signaling cascade, fruiting body development, karyogamy, and meiosis, were detected in S. schenckii and S. brasiliensis genomes, providing molecular evidence to support the potential to perform mating/sexual recombination in these species (see Table S3 in the supplemental material).…”

Fungal diseases mimicking primary lung cancer: radiologic–pathologic correlation

“…Although most cases occur in developing countries, recent immigration patterns have increased the numbers of cases appearing in the United States and Europe . PCM is caused by dimorphic fungi Paracoccidioides brasiliensis and P. lutzii , which are transmitted by an airborne route . Depending on the immune status of the host, the primary infection can resolve or develop into a progressive disease with an acute, subacute or chronic course .…”